Briefly, the inertia switch of U.S. Pat. No. 4,902,861 comprises a diaphragm that divides a casing into two chambers, electrical terminals in one of the chambers, a mass that is disposed in the other chamber and affixed to the diaphragm, and an electrical contact movable with the diaphragm for bridging the electrical terminals to provide a switch signal when the switch is subjected to a certain deceleration characteristic along the switch axis. The switch signal is supplied to the deployment system for a supplemental inflatable restraint for an occupant. The predetermined deceleration characteristic to which the switch responds is a function of the diaphragm characteristics, the mass, and the size of a control orifice which communicates the two chambers. The control orifice functions to impart dampening to the diaphragm motion because as the diaphragm moves, gas is forced between the two chambers through the control orifice and the one chamber.
One improvement that is afforded by the present invention is that such a switch is endowed with a low profile, thereby making it more compact, yet without detracting from functional and calibration capabilities. Another improvement is that an electromagnetic coil for performing a testing function can be incorporated into the inertia switch in an efficient manner. A still further improvement is that means can be incorporated to provide for the switched vacuum testing of the switch.
Additional features and advantages will suggest themselves to the reader as the description proceeds. A drawing is included and presents a preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.